你如何在连贯NHibernate一个映射的hasMany做额外的过滤？ [英] How do you do additional filtering on a HasMany mapping in Fluent nHibernate?

问题描述

在一个项目，我的工作，我有四个实体（除一堆别人的），工作单，船员，CrewAssignment和承包商。他们的关系是这样的：

In a project I'm working on, I have four entities(amongst a bunch of others), WorkOrder, Crew, CrewAssignment, and Contractor. Their relationship is like this:

• 系统工作单有一个承包商，这是可以改变的


• 系统船员永远只能有一个承包人


• 系统CrewAssignment永远只能有一个船员


• 系统工作单有很多CrewAssignments

• A WorkOrder has one Contractor, which can be changed
• A Crew only ever has one Contractor
• A CrewAssignment only ever has one Crew
• A WorkOrder has many CrewAssignments

我遇到的问题是建立的最后部分，其中一个工作单可以有多个CrewAssignments。我想要做的就是确保WorkOrder.CrewAssignments属性仅返回具有相同承包商的工作单船员的CrewAssignments。或者，少罗嗦，其中WorkOrder.Contractor == CrewAssignment.Crew.Contractor。

The problem I'm having is setting up the last part where a WorkOrder can have multiple CrewAssignments. What I want to do is ensure that the WorkOrder.CrewAssignments property only returns the CrewAssignments that have a Crew with the same Contractor as the WorkOrder. Or, less wordy, "where WorkOrder.Contractor == CrewAssignment.Crew.Contractor".

我已经能够拿出的唯一事情是这样的，但。它抛出关于x变量是不确定的异常

The only thing I've been able to come up with is this, but it throws an exception about the x variable being undefined.

HasMany(x => x.CrewAssignments).KeyColumn("WorkOrderID").Where(x => x.Crew.Contractor == x.WorkOrder.Contractor);

时做这样甚至有可能什么？还是我找错了树完全？谷歌的一上午都没有我这一个。任何想法？

Is doing something like this even possible? Or am I barking up the wrong tree entirely? Google's been failing me all morning with this one. Any ideas?

推荐答案

我不知道，如果它可以帮助你，但这里是我采取在

I don't know if it could help you but here is my take on in.

在 FluentNHibernate 您有一个名为方法在applyFilter ，你可以为了建立在你的映射过滤的子集：

In FluentNHibernate you have a method called ApplyFilter that you can set up in your mappings in order to filter on child collections :

HasMany(x => x.CrewAssignments).KeyColumn("WorkOrderID").ApplyFilter<MyFilter>().Cascade.AllDeleteOrphan(); 

然后，您可以创建过滤器：

Then you can create your filter :

public class MyFilter: FilterDefinition
{
    public MyFilter()
    {
        WithName("contractor").WithCondition("Crew.ContractorId== :contractorId").AddParameter("contractorId", NHibernate.NHibernateUtil.Int32);
    }
}

然后在你的仓库的实施，您调用过滤器：

Then in the implementation of your repository, you invoke the filter :

Sessions.EnableFilter("contractor").SetParameter("contractorId", 1254);

我不知道这是不是最好的解决办法但在我脑海权的只有一个现在。

I don't know if this is the best solution but the only one that comes to my mind right now.

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